Question

Erin covered a box with contact paper The dimensions of the box are 12 inches on the bottom 9 inches on side and 8 inches on the other side. The contact paper costs 8 cents per square inch. She will only pay fo the contact paper used to cover the box, even if there was waste or extra. How much money did Erin spend on the contact paper
A- 20.72
B- 41.44
C- 48.12
D- 73.14

Answer 1

You're just simply going to use the equation for surface area which is 
$SA=2LW+2LH+2WH$ ($or (2 * length * width) + (2* length * height) + (2* width * height)$) so you're going to plug in and then solve to get the inches squared of all the sides that Erin would cover with the contact paper.
Once you get that number you're going to multiply it by .08 to get the price.